Prior art diving face masks with such a purge valve generally include a cylindrical or box-shaped bulky portion which projects normally forwardly from a lower central area of a mask front surface to define a valve chamber where a valve is located (for example, see Japanese Kokai Utility Model No. Sho 49-33599). Such bulky configurations of the prior diving face masks have a poor appearance. More disadvantageously, the bulky configurations create increased fluid resistance, and in some instances, catch seaweeds therearound which may cause serious problems to a divers's underwater activities.
Another drawback of the prior diving face masks is that they are not configured to collect at their bottom planes, where the valve chamber is located, accumulations of water therein through leakage or the like. In such configurations, it is therefore difficult to completely discharge the accumulations of water from opening passages of the valve by the air pressure created through a single breathing stroke of the diver.
Still another drawback of the prior diving face masks is that they are not structurally designed to manage air bubbles formed as a diver's breath goes through the accumulations of water. Those air bubbles sometimes touch a diver's nares to give a diver discomfort or pain, or diffuse along the front lens to block the diver's view.